From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH] modules: add support for soft module dependencies
Date: Fri, 13 Sep 2013 09:37:33 +0930
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Cc: Andreas Robinson <andr345@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Zhao Hongjiang <zhaohongjiang@huawei.com>,
	David Miller <davem@davemloft.net>, tim.c.chen@linux.intel.com,
	Andrew Morton <akpm@linux-foundation.org>,
	"gregkh\@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	linux-crypto@vger.kernel.org,
	linux-modules <linux-modules@vger.kernel.org>,
	Tom Gundersen <teg@jklm.no>
To: Lucas De Marchi <lucas.de.marchi@gmail.com>,
	Herbert Xu <herbert@gondor.apana.org.au>
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Lucas De Marchi <lucas.de.marchi@gmail.com> writes:
> On Wed, Jul 24, 2013 at 11:03 PM, Herbert Xu
> <herbert@gondor.apana.org.au> wrote:
>> On Thu, Jul 25, 2013 at 09:32:02AM +0930, Rusty Russell wrote:
>>> Herbert Xu <herbert@gondor.apana.org.au> writes:
>>> > Hi Rusty:
>>> >
>>> > I don't know why this patch never went into the kernel, even
>>> > though the corresponding features have been added to modprobe
>>> > in most if not all distros.
>>>
>>> Because Andreas never sent me the patch?  This is the first I've *heard*
>>> of this feature.  Looks like it didn't hit lkml either.  And what was
>>> 2/2?
>>
>> 2/2 was the patch to actually use this in crc32c.
>>
>>> It's not how I would have done this: post-deps are more flexibly done at
>>> runtime, because the module may have to do work to figure out what to
>>> pull in.  But since it already exists, I'll apply this patch: it doesn't
>>> cost the kernel anything.
>
> But it did cause boot failures. The file modules.softdep file was
> supposed to be informational until now. That's why depmod put a
> comment saying to "copy on user's discretion to /etc/modules.d"
> instead of parsing it directly.

I'm happy to change this macro to create a modinfo line like
"softdep:<modname>"

ie. tools like mkinitrd could pick it up and try to find a matching
module, but depmod would ignore it.

It's really up to Lucas, since this affects him.

Cheers,
Rusty.